Altitude,Pressure, Temp...

When shooting at game at extendid distances i know all these factors play a role in shooting that far but a question that popped into my head was let's say you are shooting and elk at a 1000 yards and are in the mountains and the elk is uphill from you. You take the readings at the point where you are but the elk is at a higher elevation. Is this of concern or do the spotter rounds take care of this concern or should i say the change in the factors of shooting great distances. This may have come up before and if so excuse my post just was something i was wondering about. Thanks for any replys